<?php

namespace App\Validator\Constraints;

use App\Config\SeasonCalendar;
use App\Repository\SeasonAssignmentRepository;
use Symfony\Component\Validator\Constraint;
use Symfony\Component\Validator\ConstraintValidator;

/**
 * One season assignment per teamer per season.
 *
 * "Once a year" was a stated fact rather than an enforced one; this is what enforces it, on
 * create and on edit alike, so the teamer's season view can rely on resolving a single
 * assignment.
 */
class SeasonAssignmentValidator extends ConstraintValidator
{
    public function __construct(
        private readonly SeasonAssignmentRepository $seasonAssignmentRepository,
        private readonly SeasonCalendar $seasonCalendar,
    ) {
    }

    public function validate(mixed $value, Constraint $constraint): void
    {
        /** @var \App\Entity\SeasonAssignment $seasonAssignment */
        $seasonAssignment = $value;

        // An assignment the office has laid out but not staffed yet is a normal working state,
        // and a missing start date is the create form's own problem to report.
        if (null === $teamer = $seasonAssignment->getTeamer()) {
            return;
        }

        if (null === $dateFrom = $seasonAssignment->getDateFrom()) {
            return;
        }

        // A placement starting outside any season window belongs to no season, so there is
        // nothing to be the second of.
        if (null === $seasonYear = $this->seasonCalendar->seasonYearFor($dateFrom)) {
            return;
        }

        [$windowStart, $windowEnd] = $this->seasonCalendar->windowFor($seasonYear);

        $existing = $this->seasonAssignmentRepository->countInSeasonWindow(
            $teamer,
            $windowStart->toDateTimeImmutable(),
            $windowEnd->toDateTimeImmutable(),
            $seasonAssignment->getId()
        );

        if (0 < $existing) {
            $this
                ->context
                ->buildViolation($constraint->message)
                ->addViolation()
            ;
        }
    }
}